The highly fragmented nature of Palaeolithic faunal assemblages is a regular limitation in archaeozoological analyses as it prevents a precise taxonomic identification following comparative anatomy criteria. In this paper, we integrate Zooarchaeology by Mass Spectrometry (ZooMS) analysis of unidentifiable bone fragments within archaeozoological and taphonomic data to overcome this limitation and disentangle the subsistence strategies of Solutrean and Magdalenian human groups of the La Viña rock shelter (northern Iberia). The ZooMS results are consistent with the archaeozoological data showing preferential exploitation of red deer complemented by horses and caprids, whereas large bovids and reindeer are a minor component. This study also reveals significant species variability in classifying unidentifiable bones to mammal-size classes. The combination of biomolecular methods and traditional archaeozoology and taphonomy provides a higher resolution of faunal diversity in Palaeolithic assemblages and hominin subsistence behaviour related to carcass transport and seasonality.